Also a bugfix: make sure to render the status widget when the user doesn't have
any roster contacts.

When a user has been removed from a room and the room is still open,
we want to re-use that same room once they join it again.

As a result we now implement more status codes from the spec.
Specifically the codes related to forced removal form the room

Also fixed a bug related to wrong authentication when logging in.

To aid with dev

- list of rooms dropped off the controlbox

Try to add more information on the goals around Converse.js and on how to get
started.